Heterofunctional mucoadhesive pharmaceutical dosage composition

ABSTRACT

PCT No. PCT/FR95/00417 Sec. 371 Date Dec. 10, 1996 Sec. 102(e) Date Dec. 10, 1996 PCT Filed Mar. 31, 1995 PCT Pub. No. WO95/26713 PCT Pub. Date Oct. 12, 1995A mucoadhesive controlled-release pharmaceutical formulation comprising at least one active principle selected from the group consisting of melatonin and melatonin derivatives, composed of a first layer and a second layer, the first layer being mucoadhesive and permitting a sustained release of the active principle, and the second layer being nonmucoadhesive, and permitting a rapid release of the active principle.

The present invention relates to a pharmaceutical dosage formulationenabling products such as melatonin or its derivatives to beadministered, by combining a loading dose permitting a rapid action and,in the case of melatonin (or its derivatives), a clear chronobiologicalsignal and one or more doses released gradually, enabling products to bemade available rapidly, and in a sustained manner, in the body.

Generally speaking, the present invention relates to any mucoadhesiveformulation combining at least two formulations affording controlledreleased of different rates, ranging from a rapid form to asustained-release form.

The product is especially advantageous when the formulation is appliedto a joint administration via the transmucosal or sublingual route andvia the oral route, where the pharmaceutical dosage formulation combinesa rapid oral form with a controlled-release oral form and a transmucosalform within a single mucoadhesive buccal tablet.

Melatonin (N-acetyl-5-methoxytryptamine) is an endogenous hormonesynthesized by the epiphysis (or pineal gland) and involved, inter alia,in the regulation of the circadian rhythm, in the inhibition of gonadaldevelopment and in the regulation of ovulation.

It has the special feature of being released during the night only inmammals, and especially in human being.

In the body, this molecule is catabolized in the liver and kidneys toform, inter alia, 6-hydroxymelatonin.

An important feature of melatonin is its very marked circadian rhythm ofsecretion; in effect, the plasma levels of this hormone are low duringthe day (less than 10 pg/ml) and are high during the night (of the orderof 70 pg/ml) in human being (1, 2).

The relationship between the melatonin cycle, that is to say itsvariations in concentration in the plasma, and the sleep cycle is notclear, but melatonin may assist in organizing or reorganizing thecircadian cycles.

In the present application, melatonin and its derivatives will be usedand described as active principles administered in the heterofunctionalmucoadhesive pharmaceutical dosage composition.

It represents an especially significant example precisely as a result ofthe features of the action of this compound, which must both reach thesystemic circulation rapidly and concomitantly afford a gradual release,thus enabling the product to be made available immediately and then in asustained manner.

Any type of compound, such as melatonin derivatives substituted atposition 2 or position 6 with halogens, or alternatively any otherderivative as described in Patent Applications WO88/07367 or WO89/04659,or other substances having a pharmacological effect necessitating both arapid release ranging from a flash type release to a slow and controlledtype release, may be advantageously introduced into the pharmaceuticaldosage formulation of the invention.

Melatonin and its derivatives, bearing in mind their feature of being aregulatory factor of the circadian system, are usable, for example,during a journey across time zones for treating the phenomenon of jetlag (3). During this period, most people suffer from, among othersymptoms, mood disorders, sleep disturbance and a modification ofalertness during the daytime; various studies show, in actual fact, animprovement in the symptoms of jet lag after a melatonin-basedtreatment; more recently, it was shown that subjects who underwent 6- to12-hour time shifts showed a faster resynchronization of the differentcircadian rhythms (6-sulfatoxymelatonin, cortisol, temperature, urinaryelectrolytes, and the like) after a treatment with melatonin (4, 5).

Other applications of the regulation of circadian rhythms conferred byadministration of melatonin are, in particular:

shift work:

it has been shown that the intake of melatonin at bedtime by individualssubjected to different types of shift work (7-day shift, gradualchanges, and the like) improves the quality and duration of sleep andalertness during the period of activity (6);

blind subjects:

these subjects no longer perceive light, the main synchronizing factorof their circadian clock. Most of them nevertheless keep this clockcorrectly actuated in time with the day/night rhythm, probably becauseother signals, such as social activities, take over from the lightenvironment. However, the circadian clock of some blind people is nolonger synchronized and adopts an unfettered course, that is to say withits own period which can vary from 22 to 30 hours (7).

This leads to an alternation of periods which are favorable andunfavorable for these subjects in accordance with the synchronization orlack of synchronization relative to the day/night cycles; melatoninshould hence enable the circadian clock of these blind people to besynchronized, and make this alternation between favorable andunfavorable periods disappear;

phase-delay insomnia:

some subjects suffer from "delayed sleep" syndrome. This syndromemanifests itself in difficulties in falling asleep, difficulty in wakingup, poor alertness and a reduced level of performance. This syndromeresults from a time shift in the circadian clock relative to itsexternal synchronizing factors. Taking melatonin approximately 2 hoursbefore bedtime reduces by 2 hours the interval between retiring andsleep, and also improves the quality of the sleep (8);

this applies also, and more generally, to subjects who have disturbed orpoor quality sleep associated or otherwise with a pathology, a chronicfatigue syndrome, anxiety or depression, or with the subject's age,given that nocturnal melatonin concentrations decrease with subjects'age (9).

cancer:

melatonin administered chronically during the afternoon (50 to 500 μg)can inhibit the growth of dimethylbenzanthracene (DMBA)-inducedmalignant mammary tumors in rats (10).

Moreover, positive effects of melatonin on the progression of certaintypes of cancer (prostate, pituitary, melanoma, leukemia, and the like)have been observed experimentally in rats or mice (11); in man, somereports have suggested the therapeutic efficacy of melatonin in thetreatment of carcinoma of the lung, stomach or breast, or of leukemia(11, U.S. Pat. No. 4,855,305).

It has also been shown that there is an effect of melatonin on seasonalstress (12).

The applications of melatonin and its derivatives are very numerous, aredescribed in various publications (Patents EP513702, EP438856,WO90/14084, WO88/07367, WO89/04659) and are incorporated in this patentapplication by way of reference.

All melatonin derivatives, analogs and homologs as described, forexample, in U.S. Pat. No. 4,880,826, WO87/0432 and WO89/04659 inparticular, are also incorporated by reference in the presentapplication, as advantageous active principles of the invention.

It appears, however, that no administration route which has beendescribed has the requisite qualities of administration of thesecompounds in order, in particular, to reestablish the internal clock andthe circadian cycles, which qualities are on the one hand qualities ofwell-being since this treatment is often directed towards persons ingood health, and on the other hand qualities of short-term rapidefficacy lasting sufficiently long for there actually to be areestablishment of the rhythm with reestablishment of the differentchronobiological markers as are mentioned above.

Various dosage forms have been proposed. There may be mentioned as anexample Patent Application WO93/07870, which is a device for transdermaladministration of melatonin. This patent application claims the use ofthe already known and marketed transdermal system, for particularapplication to melatonin.

Patent Application WO91/0690 is a homogeneous bioadhesive compositionwhich permits adhesion to the mucosae, especially the buccal mucosae,for a minimum time of 6 hours, and permitting a slow and controlledadministration of melatonin exclusively via the transmucosal route.; itdoes not, however, permit a rapid action which is necessary in somecircumstances.

Patent Application EP518468 also relates to a pharmaceutical dosageformulation affording controlled release of melatonin which is a mode ofadministration selected from oral, parenteral, rectal or transdermalforms.

DETAILED DESCRIPTION OF THE INVENTION

In the description which follows, the term "pharmaceutical dosagecomposition" or "pharmaceutical dosage formulation" will be employedwithout discrimination to denote any combination of constituents usedfor pharmacological, prophylactic or therapeutic purposes.

Melatonin undergoes a very large hepatic first-pass effect which endowsit with a low or variable absolute bioavailability (measured by theratio of the plasma melatonin concentrations and by the ratio of theareas under the respective curves). In effect, comparison of thesystemic (or salivary) concentrations of melatonin after oraladministration with those obtained after intravenous administrationleads to a bioavailability which is highly variable from one subject toanother (13).

Since the metabolites of melatonin, and especially N-acetylserotonin,5-methoxytryptamine and 6-hydroxymelatonin which yields on conjugation6-sulfatoxymelatonin and 6-glucuronomelatonin (14), are inactive, theoutcome is a large variability in plasma melatonin concentrations and abioavailability which is incomplete and/or variable between individuals.

Since, furthermore, the biological half-lives of melatonin are veryshort and in the region, according to the authors, of 10 minutes for thefirst half-life and 60 minutes for the second, this leads to a searchfor an administration system that avoids the hepatic first pass (15).

The system of the invention is a mucoadhesive, controlled-releasepharmaceutical dosage composition or formulation which combines at leasttwo layers,

one (A) is mucoadhesive and permits a slow release of the activeprinciple, and in particular of melatonin or one of its derivatives,both transmucosally and orally, in particular in the saliva if thepharmaceutical dosage composition is implanted in the mouth,

the other (B) is not mucoadhesive and permits a rapid release of theactive principle or principles in the lumen of the cavity in which thepharmaceutical dosage composition is implanted, and in particular in themouth.

The target slow-transfer rates for the first layer (A) are from 0.02mg/h to 1 mg/h depending on the applications; the target rapid-transferrates for the layer (B) are from 0.2 mg/h to 10 mg/h depending on theapplications.

The term "rapid" for the rapid-release layer is understood to mean animmediate flash release which may be sustained for 2 to 5 hours. Thisnonmucoadhesive layer hence makes it possible to release a certainamount of melatonin needed to give the clear chronobiological referencesignal.

In other words, the mucoadhesive, double-layer pharmaceutical dosagecomposition of the invention has both the advantages of being pleasantto use and of being able to impart the clear chronobiological referencesignal for the desired initiation of the action; this reference signalis given by a loading dose whose speed is sufficient to lead to highplasma melatonin concentrations, such that they are far greater than theresponse threshold of all of the subjects and become, as a result,naturally recognized as such; the release is taken over by the layer oneof whose sides is mucoadhesive, which, for its part, imparts acontrolled release via the mucosal or sublingual and buccal routesmentioned above; the system permits, in addition, an adhesion to themembrane for longer than 10 hours, and the system may be withdrawn atwill at the desired final time leading to an immediate stopping of theeffects of the melatonin.

The pharmaceutical dosage composition of the invention is especiallyadvantageous when it is placed in the buccal cavity, but it isself-evident that it can be adaptable to any cavity covered with mucosa,such as the anal or vaginal cavities.

It is clearly apparent that this double-layer system is especiallyadvantageous for all active compounds necessitating a flashwise rapidtransmission into the circulatory system followed by a slow andcontrolled administration for several hours.

The double layer is one of the examples of a heterofunctionalpharmaceutical dosage formulation. Other types of heterofunctionalpharmaceutical dosage formulations may be employed, whose functions ofrapid, semi-rapid, slow or very slow release may be combined in the sameformulation: as an example, formulations such as are described in (16),in which fluidized microgranules of different formulations could bemixed and compressed with CARBOPOL® or equivalent product; the outcomeof this would also be a heterofunctional mucoadhesive pharmaceuticaldosage formulation combining a rapid release and a slow release of thesame active principle.

A feature of the pharmaceutical dosage composition according to theinvention is, more especially, that the first, mucoadhesive layer (A)contains at least:

a biocompatible polymeric resin, in particular of CARBOPOL 934P®(synthetic high molecular weight polymer or copolymer of acrylic acid)and/or polyvinylpyrrolidone (povidone) or any other biocompatibleadhesive polymer, these two resins acting as adhesion agents andparticipating in this layer in the proportion of 35 to 80% by weight ofsaid layer, and preferably 50 to 75% by weight,

a binding or diluent agent in the proportion of 5 to 40% by weight ofthe mucoadhesive double layer, and preferably 10 to 30%; such an exampleof a binding agent is dicalcium phosphate ENCOMPRESS (dicalciumphosphate) or other binding agents of the hydroxypropylcellulose orhydroxypropylmethylcellulose type or any other type of ingredientdescribed in the US Pharmacopeia XXII or USP XXII, pp. 1857-1859,

BASF METHOCEL (hydroxypropyl cellulose and hydroxypropylmethylcellulose) or any other retard agent of the hydroxypropylmethylcellulosetype or equivalent, not necessitating the addition of water, at a weightconcentration of 3 to 20%, and preferably 5 to 15%,

magnesium stearate as lubricant at a maximum concentration of 1%, anytype of lubricant as mentioned in the US Pharmacopeia XXII, p. 1858,which is also suitable as a component of this mucoadhesive layer,

AEROSIL 200 (flow promoter of colloidal silica dioxide prepared by thevapor phase hydrolysis of a silicon compound) as flow promoter, or anyequivalent such as anhydrous colloidal silica (Carboxyl, Siloid), whichis added to the layer at a maximum concentration of 1%, and preferablyat that of 0.2%,

melatonin or one of its derivatives as are mentioned above is added at aconcentration of 0.05 to 2%, and preferably 0.3 to 1.5%.

It is preferable to keep the moisture level low in the mucoadhesivelayer of the pharmaceutical dosage composition of the invention.

Such a bioadhesive layer has a water content of less than 10% by weight,and preferably less than 6%, and still more preferably less than 3% ofthe total weight of the layer.

As will be shown in the example of implementation described later, it ishence preferable to produce the whole of this pharmaceutical dosage formin a dry atmosphere or at a relative humidity below 30%.

The rapid-release layer (B) contains at least:

a polymeric resin of the CARBOPOL® type as described above as bindingagent, or any other agent providing for the same function, at a weightconcentration of 2 to 15%, and preferably 8 to 12%;

a diluent of the lactose Fast Flow grade type, or any type of diluent asdescribed in the reference table;

a disintegrating agent of the ACDISOL type (disintegrating agentconsisting in cross-linked carboxymethyl cellulose), which is acrosslinked carboxymethylcellulose, at a concentration of 1 to 30%, andpreferably 3 to 15%; it should be noted that, for this product, thehigher the percentage, the faster the release; a percentage of 30%confers a very rapid release of the active principle, whereas apercentage of 1% gives a very slow release, of the order of 5 hours, ofthe active principle;

melatonin is also added to this rapid-release layer at a concentrationof 0.2 to 10%, and preferably 1 to 6%.

As an option, it is possible to add a colorant in order to distinguishthis layer from the other one, which colorant should be added at amaximum weight/weight proportion of 1% of the compounds of this layer.

Tables 1 and 2 below show a typical composition of each of the layers(A) and (B) of the invention containing melatonin as active principle.

                  TABLE 1    ______________________________________    SUSTAINED-RELEASE MUCOADHESIVE LAYER                         Unit    Role of the                                          Percentage                Percentage                         formula constituents                                          limits    ______________________________________    Methocel    10%      15 mg   retard agent                                          3-20    Melatonin   1%       1.5 mg  active principle                                          variable    Emcompress  22.5%    33.7 mg binding agent -                                          5-40                                 diluent    Carbopol. 934 P ®                65.3%    98 mg   adhesion agent                                          35-80    Mg stearate 1%       1.5 mg  lubricant                                          max 1%    Aerosil 200 0.2%     0.3 mg  flow promoter                                          max 1%                100%     150 mg    ______________________________________

                  TABLE 2    ______________________________________    RAPID-RELEASE LAYER                                 Role of the                                          Percentage              Percentage                       Unit formula                                 constituents                                          limits    ______________________________________    Ac Di Sol 11%      5.5 mg    disintegrating                                          1-30                                 agent    Lactose Fast Flow              74%      37 mg     diluent  variable    Carbopol 934P ®              11%      5.5 mg    binding agent                                          2-15    Melatonin 3%       1.5 mg    active principle                                          variable    Colorant  1%       0.5 mg             max 1%              100%     50 mg    ______________________________________

Lastly, the invention relates to the use of such a pharmaceutical dosagecomposition as medicinal product for the treatment of sleepdisturbances, for the treatment of anxiety, and in particular ofseasonal anxiety, for the treatment of cancer and for counteractingaging.

The examples below, without being limiting in character, will show thegreat value of this type of double-layer mucoadhesive compositioncontaining melatonin for a rapid and lasting reestablishment of themelatonin level in the plasma. This example quite obviously imposes nolimitation on the use of melatonin, or on the particular composition ofthe double-layer composition used.

BRIEF DESCRIPTION OF THE DRAWING

In example I, FIG. 1 shows the plasma assay on three subjects whoaffixed the double-layer composition inside the buccal cavity, on theinside of the lower lip, at time 0 and removed it at time 7 hours. Theabscissae represent time, and the ordinates the melatonin concentrationin pg/ml (picograms per milliliter).

EXAMPLE I

manufacture of the double-layer mucoadhesive composition:

The process of manufacture of the double-layer mucoadhesive compositionis accomplished, in a first stage, by the manufacture of thenonmucoadhesive immediate- or semi-slow-release layer, and then of themucoadhesive layer, lastly followed by a final tableting of the twolayers. It is self-evident that the variant in which the mucoadhesivelayer is manufactured first, and then the immediate-release layer,followed by the final tableting of the two layers, is equivalent.

The composition produced in the example which follows is that shown inTables 1 and 2 as regards the percentages of each of the constituents.

Manufacture of the rapid- or semi-slow-release layer:

Lactose Fast Flow, Carbopol® (sieved beforehand), melatonin and thecolorant are introduced into a Turbula or equivalent mixer; theconstituents are mixed for 10 minutes.

Ac Di Sol or any other equivalent disintegrating agent is then added andthe constituents are mixed for 10 minutes.

The mixture is then stored in a suitable contained and weighed.

Manufacture of the mucoadhesive layer:

This layer is made by granulation by the dry method, and comprises thefollowing steps:

1. Carbopol 934P® is introduced into a Turbula mixer with the flowpromoter (Aerosil), the constituents being mixed for 5 minutes.

2. The mixture is then sieved through a screen of diameter 500 μm.

3. The mixture thus sieved is introduced into a Turbula type mixer andmixed for 3 minutes.

4.Melatonin is then added to the above mixture, as well as Methocel, andstirred for 10 minutes.

5. Half of the magnesium stearate or other equivalent lubricant, sievedbeforehand, is then added, and the constituents are mixed for 3 minutes.

6. The mixture is then recovered, weighed and stored in a suitablecontainer.

Compaction or first tableting:

7. The mixture of step 6 is introduced into the feed hopper of acompacter.

8. The "pebbles" of step 7 are granulated on an Erweka or equivalenttype granulator equipped with a screen of diameter 1 mm.

9. The granule of step 8 is introduced into a Turbula type mixer;Emcompress is added and the constituents are mixed for 10 minutes.

10. The second half of the lubricant, for example magnesium stearate,sieved beforehand, is added to the mixture of step 9, and theconstituents are mixed for 3 minutes.

11. This mixture 10 is stored in a suitable container and weighed.

Production of the mucoadhesive layer: second tableting:

12. The granule of step 11 is reworked and introduced into the feedhopper of the compacting machine, and tableting is thus initiated. Forthis step, the tablets should have sufficient hardness to have afriability of less than 1%, but a capacity for tableting must exist inorder to enable the final tablet to be produced.

Final tableting:

1. The mucoadhesive tablets are introduced into the first feed hopper,and the immediate-release type mixture is introduced into the secondhopper.

2. The amount of powder needed to feed the tableting chamber isadjusted.

3. Final tableting is carried out with monitoring of the hardness andweight of the final composition.

The whole of this manufacture should be carried out in a dry unit, thatis to say at an RH below 30%.

EXAMPLE II

effect of the administration of the pharmaceutical dosage composition ofthe invention on the plasma melatonin level of normal subjects:

Plasma melatonin concentrations were studied in 3 individuals treatedwith the tablet presented in Example I.

Three subjects, namely 2 men and one woman 31, 50 and 50 years of age,respectively, had melatonin concentrations on day D-1 at T0 (9.30 a.m.),T0+1 h (10.30 a.m.) and T0 +4 h (1.30 p.m.) below the limit ofquantification of the RIA method described below. Next day, on D0, theyapplied at T0 (9.30 a.m.) the mucoadhesive tablet inside the lower lipat the height of the incisor, and kept it until time T0+7 h (4.30 p.m.).

The tablet contained a 1.5 mg dose of melatonin in theprogrammed-release mucoadhesive layer and a 1.5 mg dose of melatonin inthe outer or loading dose layer.

Blood samples were drawn into heparinized tubes at times T0 (beforeinstallation of the tablet) and T0 +0.5 h, T0+1 h, T0+2 h, T0 +3 h, T0+4 h, T0+5 h, T0+6 h and T0 +7 h. After centrifugation and collection ofthe plasma, a melatonin assay was carried out by an RIA method (17, 18),in which the antibodies are obtained from Stock Grand (UK) withtritiated tracer (Amersham). This method permits a determination ofconcentrations between 10 pg/ml and 200 pg/ml. The limit ofquantification was 10 pg/ml. Appropriate dilutions were prepared forassaying the plasma melatonin concentrations on the three profiles.

The measured concentrations were as follows (see table below), and thecurve in FIG. 1 shows the subjects' mean concentration.

    ______________________________________                 Mean concentration    Time (h)     (pg/ml)    ______________________________________    0            0    0.5          254    1            1632    2            2375    3            1790    4            850    5            750    6            1050    7            283    ______________________________________

It was demonstrated that the diurnal melatonin concentrations are low,which was verified on the 3 subjects for which the concentrations werebelow the limit of quantification (<10 pg/ml) on D-1. Since theadministration was carried out on DO from 9.30 a.m. to 4.30 p.m., theplasma concentrations encountered in these 3 subjects are a reflectionof the exogenous melatonin administered by the mucoadhesive tablet.

The tablet was fully tolerated, no discomfort being experienced aquarter of an hour after it was installed and up to the time of itsremoval. The subjects felt sleepy 2 h after installation of the tablet,characterized in the 3 subjects by the desire to take a nap in one case,unaccustomed yawning in another and the sensation of having slept for 3hours the previous night (in spite of a good night's sleep) in the last.No discomfort was experienced in eating a meal from 1 p.m. to 1.30 p.m.(drink and food). The tablet was removed by mechanical action of thefinger. This administration resulted in no general or local side-effect,showing an excellent clinical tolerability of the tablet.

CONCLUSION

Such pharmaceutical dosage compositions as described above in theinvention are especially advantageous on several grounds.

The first is the convenience of use, since compounds which adhere to theinside of the mouth on the mucosa are relatively stable, permit normaleating and are not uncomfortable for the subjects.

Another advantage is that, immediately the tablet is removed, the plasmamelatonin concentrations decrease and fall below the limit ofquantification.

The essential advantage is clearly apparent from inspection of FIG. 1,which shows unmistakably the immediate flash effect conferred as aresult of the nonmucoadhesive layer (B), followed by a controlled andcontinuous release as a result of the second, mucoadhesive layer. By wayof comparison, this curve may be compared with the curves given, forexample, in Patent EP 518468, in which the appearance of melatonin inthe plasma is relatively slow, mimicking the normal cycle of appearanceand disappearance during the night.

The plasma kinetics of melatonin given in FIGS. 5 and 6 of PatentApplication WO93/07870 reveal a slow increase in the melatoninconcentration in the plasma (see, in particular, FIG. 6 and FIG. 8 ofsaid patent).

The same observation may be made regarding the plasma kinetics ofmelatonin obtained from the bioadhesive composition described in PatentApplication WO91/06290, which show a slow and continuous increase inmelatonin in the plasma as a result of the sustained release of theactive principle.

No system has shown the twofold advantage of immediate transfer followedby a semi-slow and controlled release throughout the period ofmaintenance of the pharmaceutical dosage composition of the invention onthe mucosa.

BIBLIOGRAPHY

1. Lewy A. J., Wehr T. A., Goodwin F. K., Newsome D. A., Markey S. P.,1980. Light suppresses melatonin secretion in humans. Science 210:1267.

2. Arendt J., Broadway J., 1987. Light and melatonin as zeithcibers inman.

3. Arendt J., Aldhous M., English J., Marks V., Arendt K. H., Marks M;and Folkard S., 1987. Some effects of jet lag and their alleviation bymelatonin. Ergonomics, 30:1379.

4. Samel A., Maas H., Vejroda M., Wegman H. M., 1989. Influence ofmelatonin treatment on human circadian rhythmicity. in "Aviation, Spaceand Environmental Medicine" Abst 485, p. 52.

5. Nickelsen T., Land A., Bergau L., 1991. The effect of 6-, 9- and11-hour time shifts on circadian rhythms: adaptation of sleep parametersand hormonal patterns following the intake of melatonin or placebo. In"Advances in Pineal Research: 5", Arendt J., Pevert P. (Eds), JohnLibbey & Co Ltd., p. 306.

6. Folkard S., Arendt J., Clark M., 1990. Can melatonin improve shiftworkers' tolerance of the night shift? Some preliminary findings.Interdisciplinary Cycle Research, Proceeding of the European Society forChronobiology.

7. Aldhous M., Arendt J., 1991. Assessment of melatonin rhythms and thesleep-wake cycle in blind subjects. in "Advances in Pineal Research:5",Arendt J., Pevet P. (Eds), John Libbey & Co Ltd., p. 307.

8. Tzischinsky O., Dagan Y., Lavie P., 1993. The effects of melatonin onthe timing of sleep in patients with delayed sleep phase syndrome. in"Melatonin and the pineal gland"--from Basic Science Publishers P.V., p.351.

9. Touitou Y. et al., 1981. "Age- and Mental Health-Related CircadianRhythms of Plasma Levels of Melatonin, Prolactin, Luteinizing Hormoneand Follicle-Stimulating Hormone in Man", J. Endocr. 91:467-475.

10. Tamarkin L., Almeida O. F. X., Danforth D. N., 1985. Melatonin andmalignant disease.

11.Blask D. E., 1993. Melatonin in oncology. In "Melatonin:biosynthesis, physiological effects, and clinical applications", Yu H.S., Reiter R. J. (Eds), CRC Press, Boca Raton, Fla., p. 447.

12. Wirz. Justice et al. (1990). J. Psychiat. Res. 24(2):129-137.

13. Waldhauser F., Waldhauser M., Lieberman R. et al., 1984."Bioavailability of Oral Melatonin in Human". Neuroendocrinology39:307,313.

14. Hing Sing Yu 1993.

15. Mallo C., Zaidan R., Galyg et al. 1990. "Pharmacokinetics ofMelatonin in Man after Intravenous Infusion and Bolus Injection". Eur.J. Clin. Pharmacol. 38:297-301.

16. RITSCHEL W. A. et al. Peroral solid dosage forms with prolongedaction in DRUG DESIGN, vol. 4 (E. J. ARIEN Ed.), Academic New York,1973, chap. 2, p. 37.

17. Arendt J., Sizonenko P. C., Pauniner L. "MelatoninRadioimmunoassay". 1975. J. Clin. Endocrinol. Metab. 40:347-350.

18. Howanitz P. J., Howanitz J. H. 1983. "Direct Radioimmunoassay forMelatonin in Plasma". Clin. Chem. No. 2, 29:396-397.

I claim:
 1. A mucoadhesive controlled-release dosage pharmaceuticalformulation comprising at least one active principle selected from thegroup consisting of melatonin and melatonin derivatives; and composed ofaa first layer and a second layer, said first layer being mucoadhesiveand permitting a sustained release of the active principle at a rate of0.02 mg/h to 1 mg/hr both transmucosally and orally, and said secondlayer being nonmucoadhesive, permitting a release of the activeprinciple at a rate of 0.2 mg/h to 10 mg/h,wherein said first layercomprises at least: a biocompatible acrylic acid polymeric resinadhesion agent in a concentration of 35 to 80 weight %, ahydroxymethylcellulose or hydropropylcellulose diluent binding agent ina concentration of 5 to 40 weight %, a hydropropylmethylcellulose retardagent in a concentration of 3 to 20 weight %, a magnesium stearatelubricant in a maximum of 1% by weight, a flow promoter at maximumconcentration of 1 weight %, and said at least one active principle;said second layer comprises at least: an acrylic acid or polyvinylpyrrolidone polymer at a concentration of 2 to 15 weight %, adisintegrating agent at a concentration of 1 to 30 weight %, said atleast one active principle; a lactose diluent in a concentration of from60 to 80 weight %, and optionally, a colorant at a maximum concentrationof 1 weight %.
 2. The formulation according to claim 1, wherein saidmelatonin, or derivative thereof, is in an amount of 0.05 to 2 weight %.3. The formulation according to claim 1, wherein said melatonin, orderivative thereof, is in an amount of 0.3 to 1.5 weight %.
 4. Theformulation according to claim 1 wherein the retard agent is present ata concentration of 8 to 12 weight %.
 5. The formulation according toclaim 1 wherein the diluent binding agent is present at a concentrationof 15 to 30 weight %.
 6. The formulation according to claim 1, whereinthe adhesion agent is a synthetic high molecular weight polymer orcopolymer of acrylic acid at a concentration of 45 to 75 weight % insaid first layer and 8 to 12 % in said second layer.
 7. A method ofrapid and sustained restoration of an active principle selected from thegroup consisting of melatonin and melatonin derivatives, in a mammalcomprising administering the formulation of claim 1 to said mammal.
 8. Amethod of rapid and sustained restoration of an active principleselected from the group consisting of melatonin and melatoninderivatives, in a mammal comprising administering the formulation ofclaim 2 to said mammal.
 9. A method of rapid and sustained restorationof an active principle selected from the group consisting of melatoninand melatonin derivatives, in a mammal comprising administering theformulation of claim 3 to said mammal.
 10. The method according to claim7 wherein said mammal is a human in need of treatment for sleepdisturbances.
 11. The method of claim 7 wherein said mammal is a humanin need of treatment of anxiety.
 12. The method of claim 11 wherein saidanxiety is seasonal anxiety.
 13. The method of claim 7 wherein saidmammal is a human.
 14. The formulation according to claim 11 whereinsaid active principle is melatonin.